So, when I bought my first bike with disc brakes they started rubbing after the first ride. It was driving me insane so I took it to a bike shop and asked them if it was a problem. They said “ah no, no problem. It will go away after a while.” So this didn’t make me too happy so I looked into it and found out how to fix the problem Caliper Inch/Metric/Fractions Conversion 0-6 Inch/150 mm b017kuc6xq.
Disc brakes can be sensitive and the caliper can move around when you hit some bumps on the trail. Fortunately its not hard to fix. Most calipers are attached to the fork with two bolts, and the bolt holes on the caliper are bigger than the diameter of the bolt. Allowing you to loosen the bolts and move the caliper a little ways side to side. If your caliper does not have an adjustment bolt on the side of it, this is the way you have to adjust them.
Fortunately, most disc brakes have bolts on the caliper that allow you to move the brake pads in or out. The caliper will be marked close to the bolt telling you which way to rotate it to move the brake pad in either direction. You can also use this adjustment to make the brake feel tighter or looser, but be careful, once your brake pad wears down far enough, if you adjust the pad too far inwards you could rub your rotor on the steel of the caliper. That is just about the only problem you can run into with that.